This invention relates to a declogging system and more particularly to a system for assuring the fluidization of material conveyed in a pneumatic conveying system.
In the prior art, there has been developed a system for pneumatically conveying a bulk particulate material generally consisting of a first conduit formed of a gas permeable material having an inlet and an outlet, a second conduit formed of an impermeable material encompassing and spaced from the first conduit, a plurality of partition walls disposed between such conduits and spaced along the lengths thereof, providing a plurality of plenums, means connectable to a source of gas under pressure for injecting a gas into the first conduit to impel material deposited therein and means for supplying such plenums with a supply of gas under pressure which has the effect of permeating the interior, permeable conduit, forming a boundary layer consisting of air and entrained material being conveyed and thus enhancing the flowability of material being conveyed. Such a system is illustrated and described in U.S. patent applications, Ser. No. 09/883,486, filed Jun. 18, 2001, now U.S. Pat. No. 6,609,871, and Ser. No. 10/223,381, filed Aug. 20, 2002, which are incorporated herein by reference.
In the type of system as described, following a period of use in service, it has been found that some materials being conveyed have the tendency to accumulate on the inner surface of the inner, permeable conduit, forming a crust which over a period of time begins to clog the openings in such conduit. With encrustation, the fluidization efficiency is impaired by the clogging of the pores in the permeable conduit, which increases the pressure drop across the conduit and correspondingly reduces the flow rate of fluidizing gas. Encrustation also reduces the cross-sectional area of the conveying line, which correspondingly increases the resistance to conveying flow. Accordingly, it is the principal object of the present invention to provide a system complimentary to the type of system as described for preventing such encrustation and assuring the supply of fluidizing gas and correspondingly minimizing if not eliminating the pressure drop along such a conveying line.
The present invention obviates the potential problem of clogging of the apertures in the inner, permeable conduit in a system of the type described, and the attendant pressure drop along the conveying line by providing a complimentary system including means connected to an additional source of gas under pressure operable for selectively supplying the plenums of the conveying line with bursts of gas under pressure for dislodging material clogging the apertures in the inner, permeable conduit of the conveying system. Preferably, such complimentary system is operable to periodically supply such bursts of gas progressively to such plenums along the length of the conveying line.